Electron Spin Resonance Spectroscopy of a Single Carbon Nanotube Christopher O’Connell1,2, T. Endo3, J. Kono1, and Y. Ochiai3 1.NanoJapan Program, Department of Electrical & Computer Engineering, Rice University, USA 2.Department of Mechanical Engineering, University of Rhode Island, USA 3.Graduate school of Advanced Integration Science, Chiba University, Japan Introduction Sample uv MWCNT Sample-making process Carbon nanotubes provide an ideal one-dimensional system in which to study exotic quantum mechanical behaviors of electrons. In particular, metallic single-walled carbon nanotubes are predicted to possess some unique properties arising from electron-electron interactions under extreme quantum confinement. Here we use electron spin resonance, or ESR spectroscopy, to elucidate electronic states of carbon nanotubes in magnetic fields. 1-D Electron Flow Electrode mask SiO2 Photoresist Si Disperse Dicholoroethane CNT solution on substrate Spin coat and select ideal Nanotube Apply Photoresist Using an electrode mask, expose the sample to UV light 15-20mm MWCNT Theory predicts that so-called ‘spinons’ and ‘holons’ show different amounts of Zeeman splitting, leading to splitting of an ESR peak, which, if observed, can be taken as direct evidence of spin-charge separation of a Luttinger liquid. Our goal was to confirm this theory experimentally. Microwave Radiation (n) Field Off B=0 UV exposed photoresist is lifted Vapor deposition of Ti and Au electrodes Remove excess resist in Acetone Electrode bonding Finished Samples (Magnification x100) E Field On B≠0 Results A The weak ESR signal of the bulk CNT directly correlated to the defined signal of the Si/SiO2 sample. The symmetric (A=B) lineshape appears to be Lorenztian with the following parameters: B Spinon Holon Corrected signal without Si Original data with Si and C ESR Apparatus Lockin Amplifier Microwave generator Carbon Cavity sample holder ESR Spectrometer A varying applied magnetic field (B) of under 1 Tesla causes degenerate free electrons to split in energy. Constant microwave radiation (n) causes electrons to jump states equal to the energy difference. Lockin amplifier A change in temperature and resistance allows us to detect the CNT ESR resistively using an eLockin 204 Amplifier. Silicon g-value = 1.982537 Linewidth ~ 30 gauss n B Sample B Discussion The obtained results above are from a small ensemble of nanotubes dispersed throughout the surface of the substrate. The broad lineshape was confirmed to be the resonance signal from Si and the sharp and defined lineshape that of the nanotubes. The ESR resistance measurement was not completed due to equipment and sample difficulties but will be continued in hope to confirm the spin-charge separation prediction of SWCNT and MWCNT. Electromagnet (x2) Sample ESR! T=C R=C T=DT R=DR Lockin Amplifier Before Resonance: Temperature and Resistance remain constant During Resonance: Temperature will increase resulting in a change in Resistance http://nanojapan.rice.edu This material is based upon work supported by the National Science Foundation under Grant No. OISE‐0530220. This research was also partly supported by the University of Rhode Island College of Engineering.